One way to do it, is to completely turn off the admin interface (i.e. you have to specify exactly which kind of interface you would like your client is supporting). I don't know whether it is possible to turn off single commands inside an interface :/ Maybe to do this, you have to re-compile geth from scratch
– BriomkezSep 13 '18 at 18:03

@Briomkez That would be just perfect but I don't know how to disable a module in the console. I'm actually re-compiling gets all the time.
– Javier SagredoSep 13 '18 at 18:32

Eventhough this virtually has the desired behavior, I'd prefer that no-one is able to use the admin module. With this option that you are considering, someone could put his node down and restart it with the admin api enabled. A more precise solution shall be to remove entirely from the code but I'm not quite sure where is it declared and used.
– Javier SagredoSep 14 '18 at 7:27

With ipc you can send commands only if you are executing in the same machine (so only you can access to the api) with rpc and ws you can disable the admin interface and also restrict the ip from which you accept commands (with the option rpccorsdomain)...
– BriomkezSep 14 '18 at 12:14